Histochemical responses in the retina after acute blood loss

Adult albino mice were bleed through the hearts by cardiac puncture under Nembutal anesthetic. 0.3 ml of blood was withdrawn form every animal. The retinae were then studied on a timed basis with succinic dehydrogenase histochemistry and alkaline phosphatase histochemistry. In control retinae, high SDH activities were localized in the inner segments, outer plexiform, inner plexiform, and ganglion cells layers and high alkaline phosphatase activities were localized in the ganglion cell layers and the vessels of the plexiform layers. Decrease in the enzymatic activities of both SDH and alkaline phosphatase in these layers were most evident 5h after bleeding. 9 to 24 h after bleeding, a compensatory increase was detected. 48 to 72 h after, the enzymatic activities decreased again. Reperfusion of experimental animals with 5% dextrose would increase the retinal enzymatic activities back to normal, even if the reperfusion was carried out as late as 48 h after bleeding.